<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
    <script src="../../jQuery/jquery-3.3.1.min.js"></script>
</head>
<body>
<script type="text/javascript">
    function xianshi() {
        $("#imgID").fadeIn;
    }
    function yuncang() {
        $("#imgID").fadeTo(300, 0.1);
    }
</script>
<img id="imgID" src="../img/11.png" width="30%"></br>
<input type="button" value="点我显示" onclick="xianshi()">
<input type="button" value="点我隐藏" onclick="yincang()">
</body>
</html>